Such welding methods are known from the prior art, for example, DE 10 2007 028 956 A1, DE 10 2007 027 226 A1, DD 268 418 and EP 0 743 133 A1. However, these welding methods do not enable operationally reliable clamping, in particular of very thin metal sheets, since, as a result of the flexibility thereof, undesirable fluctuations in the gap dimension occur. This results in very high undesirable rejection rates. Furthermore, in the event of a thermal connection operation, for example, laser welding, electron beam welding, CMT arc welding, in particular connection of non-identical materials, for example, aluminum/steel, there are formed in the melt bath intermetallic phases whose type and thickness are difficult to control but which have a decisive influence on the stability and the fatigue strength of the connection.